Sting cancelled a performance in Kasakhstan, but did go ahead with a concert in Uzbekistan in 2009.

Musical boycotts were back in the headlines last week, when Sting called off a concert appearance in Astana, Kazakhstan on July 4. The singer cancelled the date on his current Symphonicity tour in solidarity with striking oil workers in the central Asian republic. Sting commented on his website that "hunger strikes, imprisoned workers and tens of thousands on strike represents a virtual picket line which I have no intention of crossing".

The concert cancellation follows hot on the heels of embarrassing revelations earlier this year that stars including Mariah Carey, Nelly Furtado and Beyoncé had performed in recent years for members of Libya's Qaddafi family. With the PR damage these ill-chosen dates have wreaked proving difficult to contain, it seems that musicians are now more wary than ever of being tainted by association with unpopular regimes.

Certainly the decision by Sting represents a notable change of heart on the singer's part. In 2009, he acted quite differently in a not dissimilar situation in Kazakhstan's neighbour Uzbekistan. Back then he was paid $1.6 million (Dh5.87m) to perform for the Uzbek president Islam Karimov's daughter - the same President Karimov who has been accused of human rights violation. Sting's association with the regime sparked a furious public reaction. Matters were not helped by Sting's mistaken claim that the concert, with tickets on sale at $1,000, was sponsored by Unicef. Despite this, Sting defended his choice, stating that he had "come to believe that cultural boycotts are not only pointless gestures, they are counter-productive".

Sting's different reaction this time shows he is keen to ward off a second backlash - although, certainly, Kazakhstan's human rights record is better than that of Uzbekistan. The decision seems to be about more than his recent troubles alone, however.

One of the unlikely ripples caused by this year's Arab Spring is that music stars are increasingly under scrutiny for their professional relationships with the powerful. The squeaky-clean image of stars such as Beyoncé sits uncomfortably with that of states such as Libya, so revelations that she, Carey and Furtado had all performed at private parties thrown for Qaddafi's children came as a shock. What must have seemed like easy money at the time became a PR nightmare for the singers, fostering a climate where musicians think much harder about where they play and for whom.

Whatever the true reason, Sting's withdrawal from Kazakhstan is just one of a long line of musical boycotts. In 1964, the British soul singer Dusty Springfield withdrew from a South African tour after refusing to perform to whites-only audiences.

Following Springfield, many musicians turned down South African tours, though in the 1980s the Sun City casino complex started hosting boycott-busting stars including Frank Sinatra and Tina Turner. This backsliding created a fight-back in the form of the protest record (I ain't gonna play) Sun City, featuring musicians including U2, Bruce Springsteen, Run DMC and Lou Reed.

More recently, many musicians have joined the cultural boycott against Israel, including artists such as Elvis Costello, Barbra Streisand, Gorillaz, Carlos Santana and The Pixies.

It's not just whole countries that have been the subject of musical protests. Last year, Kanye West, Shakira and Rage Against the Machine refused to play in the US state of Arizona after a state law gave police powers to stop and search anyone they suspected of being an illegal alien. Not all musicians support the concept, however. Elton John, who played South Africa under apartheid and Israel last summer, recently attacked the Arizona boycotters in extremely strong language.

Critics of musical boycotts point out that performing internationally is a way of engaging concertgoers in dialogue, giving them the chance to hear alternative voices. Whether this is true or not (Uzbekistan's record has not notably changed after Sting's last visit), tainting themselves by association seems to be a risk pop stars are increasingly reluctant to take.